1. Field of the Invention
The present invention relates to a method of sealing electric and electronic parts which may be used for, for example, sealing switches employed in brake oil level alarms for automobiles.
2. Description of the Related Art
In a conventional electric parts sealing method related to the present invention, thermosetting epoxy resins have heretofore been used to seal switches employed in brake oil level alarms for automobiles.
However, since hermosetting epoxy resins usually take long periods of time to set, i.e., 1 to 2 hours, ultraviolet-curing resins have been used recently.
There are a variety of ultraviolet-curing resins, among which polyester acrylate, epoxy acrylate, urethane acrylate, epoxy, silicone resins are generally put into practical use (see the September 1981 issue of "Toso Gijutsu (Painting Technique)", p. 15).
Among the above-described ultraviolet-curing resins, polyester acrylate, epoxy acrylate, epoxy and silicone resins can be only cured to a depth of about 2 to 3 mm and therefore cannot be used for switches employed in brake oil level alarms for automobiles which require a curing depth of 5 mm or more.
Urethane acrylate resin can be cured to a depth of 5 mm or more but is inferior in terms of chemical resistance and oil resistance and therefore cannot be used for parts to which oil or the like is readily attached, such as switches for brake oil level alarms.